HELP! Prop for O.S. 1.60FX
 

About the last thing I need to pick out for my Ohio RC 23% Extra 300S (70" wingspan, 11 lbs) is the prop. I have an O.S. 1.60FX 2-stroke engine (a lot of power, I know, but I got a screaming deal on the plane with the engine, and it's brand new!).

Looking at prop choices for this engine, I see some ranging from 16x10 to 18x14. Just glancing through Tower Hobbies, I found some 18x10s by Dynathrust, but they say they are for 4-stroke engines (wider chord, I guess). Can I use this?

APC makes some that are that size also, but they're twice as expensive. Not that I'm cheap, but I'd like to spend less for the first few props until I get used to the plane.

Wood vs. Nylon/Composite? Again, I don't know how many props I'll go through if I choose wood....one nose-over and POOF! There goes another $15.

Any suggestions would be GREATLY appreciated.

Thanks,

Rich

RE: HELP! Prop for O.S. 1.60FX
 

I think a Zinger 18X6-10 would be a good place to start. A Menz or Zinger 20X6 is another suggestion. Use any prop that keeps the engine RPM in the 6500 to 7500 range and you should be okay...

I am basing this on research I did for my ST-3000 and I think it will apply to the O.S. too...

RE: HELP! Prop for O.S. 1.60FX
 

Spend the money for the APC and look at the 17 or 18 inch size...

scott

RE: HELP! Prop for O.S. 1.60FX
 

This engine really like the 18 inch props, 20 is a bit on the big side for the 1.60 based on what I have seen. With an 18 x 6 Zinger mine tachs about 9K, power is phenomenal. Anything over 9K starts to get pretty loud and I got nervous when I tried a 16 x 6/10 Zinger on mine, sounded like it was going to toss a blade off. The 3D guys like the APC 18 x 6 and say it's the king for raw thrust but the weight of the prop is up there and the 1.60's spool up time is sorta lacking compared to using a wood prop.

I tried the 18 x 6 Zinger Pro on mine and to be honest I like the regular plain old Ziner 18 x 6 the best. The 18 x 8 and 18 x 10's are a possibility but remember that pitch = speed so the higher the pitch the greater the speed that the prop works in, consequently your landing speeds will typically be higher with 8 and 10 pitch props.

RE: HELP! Prop for O.S. 1.60FX
 

I know a guy who flies his with a Menz 20x6. Hoowowie that thing's got some static thrust!

RE: HELP! Prop for O.S. 1.60FX
 

Aaron,

Do you know what RPM he is getting with this prop? OS claims best HP @ 9000, but doesn't say where best torque is...

RE: HELP! Prop for O.S. 1.60FX
 

Well, I noticed that with the Great Planes Extra 300S 1.60 that's reviewed here at RCU, they used an APC 18x6W and they got phenomenal performance (check out the videos in the review!). That plane's a little bigger than mine (4" more wingspan and about 1.5 lbs), so mine should scream with that one. I'm going with the APC 18x6W.

Thanks, guys!

--Rich

RE: HELP! Prop for O.S. 1.60FX
 

Galen, sorry I don't. Tachs aren't the most popular tool at my field. If someone's got one next time I hook up with him, I'll get a reading.

RE: HELP! Prop for O.S. 1.60FX
 

There's a thread about propping this engine that was started over a year ago and Aerosplat tried a number of props out, search for it and grab a cup of coffee.

If I remember correctly the APC 18 x 6W was the king of thrust for this engine but since the prop is pretty heavy it has a pretty slow spool up. For 3D flying having that throtttle response is probably more important than the extra thrust that the APC provides. Now if your not into flying 3D none of that matters.

RE: HELP! Prop for O.S. 1.60FX
 

I also am using a Turbo-Jett muffler with this engine ([link=http://www.jettengineering.com/accy/turbo.html]http://www.jettengineering.com/accy/turbo.html[/link]). This muffler is 75 grams lighter than the stock O.S. muffler. I contacted Jett Engineering and they told me that they tested a 20x8 prop and it was a great choice for this engine and muffler combination. The Turbo-Jett muffler increased the RPM by 550 with over a stock O.S. muffler with a 20x8 prop (came out to 7,800rpm).

So I think I may get BOTH a 20x8 and an 18x6W and compare them with this engine.

--Rich